Radioactive iodine therapy for thyroid cancer
Radioactive iodine therapy is a treatment that uses radiation to treat thyroid cancer.
What is radioactive iodine therapy?
- Radioactive iodine therapy is a treatment that uses radiation to treat thyroid cancer. The radiation comes from a radioactive substance called iodine-131.
- Not all patients need radioactive iodine therapy. You will be referred to a specialist centre for this treatment if you need it.
- This therapy can destroy tiny amounts of normal thyroid tissue or any cancer cells left behind after surgery. It is usually given after surgery for papillary or follicular thyroid cancer. You may have to wait several weeks to recover after surgery before having this treatment.
Preparing for radioactive iodine therapy
You will need a high level of thyroid-stimulating hormone (TSH) in your bloodstream for the treatment to be a success. This is done by giving an injection of TSH before treatment. The hormone activates thyroid cells and encourages them to absorb the radioactive iodine.
Taking recombinant TSH: You will continue on your hormone therapy and be given recombinant human TSH (rhTSH). The drug is given over 2 days before the iodine capsule is taken. It boosts the level of TSH in your body to make sure the radioactive iodine therapy works.
If there’s less iodine in your body it will be more willing to take up the radioactive iodine, so you may be told to limit the iodine in your diet for 2 weeks before your treatment. Your nurse will tell you what foods to avoid.
Use a reliable method of contraception before you start treatment – it’s important not to become pregnant or father a child during treatment and for a few months afterwards. Ask your doctor about this. Tell your doctor if there’s a chance you might be pregnant. Radioiodine treatment can harm the baby and so isn’t suitable if you are pregnant or might be pregnant.
If you are breastfeeding, you must stop 8 weeks before your treatment. In fact, it is best if your child is weaned before treatment, or postpone it until your baby is weaned. It is not safe to start breastfeeding again after your treatment, but future pregnancies and breastfeeding will not be affected.
Getting radioactive iodine therapy
Usually you will be given a small pill. The radioiodine goes into your bloodstream and travels to thyroid cells in your body. The thyroid cells absorb the radioiodine and it kills them.
Other cells in your body will not be harmed as they do not absorb the radioiodine. The treatment can be repeated if thyroid cells are still present.
After radioactive iodine therapy
The therapy makes you radioactive for a few days. There is a chance that the hospital staff and your relatives and friends might be exposed to the radiation. Because of this, certain safety precautions are taken while the radioiodine is still in your body.
- No visitors are allowed for the first 24 hours. After that they are only allowed in your room for a short time each day, one at a time.
- Children under 14 and pregnant women will not be allowed to visit you for up to 5 days.
Some hospitals might have other precautions not listed here. These will be explained to you in more detail before your treatment.
It is best to drink lots of fluids as this will get rid of the radioactivity quicker. The medical physicist will measure your radiation levels every day to make sure they have dropped to a safe level. Usually after 3 days you will be allowed home. Usually a whole body scan is done before you go home or the following week.
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